Ventura County Sheriff Geoff Dean told the press that his department received multiple calls of shots fired at Borderline Bar & Grill in the city located 40 miles from downtown Los Angeles.

The bar was hosting “College Country Night” and was filled with students, per reports.

Three minutes after calls were made, Sgt. Ron Helus and another officer went in to confront the gunman. Helus, a 29-year police veteran, was shot multiple times and later died from his injuries.

“He was hardworking, he was totally committed, he gave his all and, tonight, as I told his wife, he died a hero,” Dean said. “He gave his life to save other people.”

Dean said when other officers arrived at the scene, they discovered 11 people were dead, including the suspect.

“They found people hiding in restrooms, people hiding in attics,” said Dean. “It’s a horrific scene in there; there’s blood everywhere.”

Witnesses reportedly used barstools to break windows to escape, per NBC News.

“They were just young people, like 18, 19, 20, just having a great time, then this maniac came in and started shooting people for no reason at all. These people have never hurt anybody in their lives. They’re kids, they’re just kids, I’m sorry,” a witness told KABC-TV.

President Donald Trump tweeted that he had been briefed on the shooting.

“I have been fully briefed on the terrible shooting in California. Law Enforcement and First Responders, together with the FBI, are on [the] scene,” he tweeted.

I have been fully briefed on the terrible shooting in California. Law Enforcement and First Responders, together with the FBI, are on scene. 13 people, at this time, have been reported dead. Likewise, the shooter is dead, along with the first police officer to enter the bar….

According to Capt. Garo Kuredjian of the sheriff’s office, Thousand Oaks, which was ranked the third-safest city in the country in 2018, is “a very safe community” and shootings don’t “happen very frequently in our neighborhood.”